Field of the Invention
The present invention relates to an automatic tracking apparatus, and particularly to an automatic tracking apparatus that automatically changes the shooting direction of a camera to automatically track a desired object.
Description of the Related Art
Conventionally, an automatic tracking apparatus has been known that performs zooming, panning and tilting of a camera platform mounted with a television camera to change the angle of view of an image acquired by the camera and the direction of the optical axis direction, thereby automatically tracking a moving object. Here, if the panning or tilting operation is performed when the object moves quiveringly within an image pickup range of the camera, an image with a shaking screen is acquired. To prevent the shake, a method has been known that provides a tracking operation prohibition area in which no tracking operation on the camera platform is performed when an object remains in a certain area.
For instance, Japanese Patent Application Laid-Open No. 2001-169170 discloses an example of changing the range of a tracking operation prohibition area (dead zone) according to the position of an object in a screen. Japanese, Patent Application Laid-Open No. 2002-171438 discloses an example of Changing a tracking operation prohibition area according to the traveling speed of an object.
According to the conventional art disclosed. it Japanese Patent Application Laid-Open No. 2001-169170, when the object moves from the center at high speed, the object gets out of the screen because the dead zone is wide; there is a possibility of losing track of the object. However, if a small dead zone is preset, a phenomenon cannot be prevented in which an image with a shaking screen is acquired when an object quiveringly moves as described above. According to the conventional art disclosed in Japanese Patent Application Laid-Open No. 2002-171438, if the speed of an object abruptly changes, track of the object is sometimes lost.